test(chat): enforce locked image URL masking

src/data/mock/chat/responses/send-message-photo-paywall.json

@@ -10,7 +10,7 @@
     "timestamp": 1782180725000,
     "image": {
       "type": "elio_schedule",
-      "url": "https://cdn.cozsweet.com/mock/chat/elio-schedule-locked.jpg"
+      "url": null
     },
     "lockDetail": {
       "locked": true,

src/stores/chat/__tests__/chat-helpers.test.ts

@@ -185,12 +185,12 @@ describe("sendResponseToUiMessage", () => {
     expect(message.privateMessageHint).toBeUndefined();
   });
 
-  it("keeps paywalled image messages visible but locked", () => {
+  it("keeps image messages locked without retaining the protected URL", () => {
     const message = sendResponseToUiMessage(
       makeResponse({
         image: {
           type: "jpg",
-          url: "https://example.com/private-photo.jpg",
+          url: null,
         },
         lockDetail: {
           locked: true,
@@ -199,9 +199,9 @@ describe("sendResponseToUiMessage", () => {
       }),
     );
 
-    expect(message.content).toBe("");
-    expect(message.imageUrl).toBe("https://example.com/private-photo.jpg");
-    expect(message.imagePaywalled).toBe(true);
+    expect(message.content).toBe("AI reply");
+    expect(message.imageUrl).toBeUndefined();
+    expect(message.imagePaywalled).toBeUndefined();
     expect(message.locked).toBe(true);
     expect(message.lockReason).toBe("image");
     expect(message.lockedPrivate).toBeUndefined();